Posted
by
CmdrTaco
on Thursday January 10, 2008 @11:41AM
from the this-is-gonna-burn-my-crotch-isn't-it dept.

mfbatzap writes "According to Firdooze, we have seen various devices that can free ourselves from wires at CES 2008. The manufactures, Wildcharge, Powercast and Fulton Innovation, came out with two different methods of transmitting power from source to the devices. Wildcharge and Fulton banked on magnetic coupling while Powercast decided to go with RF (Radio Frequency). So which technology will eventually prevail to be the future of wireless power? Or will the technological setbacks from transferring power wirelessly make it unrealistic to accomplish a wire-free world?"

well, I experimented with this. While the tumors were benign to me, after the third or fourth time I woke up to find one gnawing on the limb of a small child it apparantly captured/ate/killed, I decided it was time to have it removed. Apparantly three doctors were lost during the procedure.

Probably. Just make damned sure that the transmitter produces frequencies which couple strongly only to the receiver (very small bandwidth). Things which don't resonate at those frequencies will be essentially transparent to the signals. I suggest 2.45 GHz!

From what I understand, it depends on the frequency. For instance, a microwave oven operates at whatever frequency best excites a water molecule, which leads to cooking by making the water in everything hot.There was a long-running experiment in California back in the seventies or so that transmitted kilowatts of power over a few kilometers. They were doing the test as a lead-in experiment to figure out whether or not satellite-based power generation and transmission was feasible.

From what I understand, it depends on the frequency. For instance, a microwave oven operates at whatever frequency best excites a water molecule, which leads to cooking by making the water in everything hot.

That is incorrect, but you're forgiven because it is a common misconception that's even in a few encyclopedia's and such.

Microwaves work by producing an alternative electric field (using non-ionizing microwave radiation) that acts on molecules which have electric dipoles. Water is one of those, but so are many others, including fats and such. The process is called Dielectric Heating.

Basically, the molecule being heated is a dipole. It has a positive charge at one end, and a negative charge at the other. In an alternating electric field, it rotates as it tries to align itself with the field. This causes motion, which translates to heat. The heat spreads as the molecules hit other molecules and transfer the energy to them. Now, this process works really good on water because water is a very strong dipole, but it does not operate solely on water, and it doesn't have anything to do with water in particular.

See, the frequency doesn't actually have much to do with it. Normal kitchen microwaves operate at 2.4 Ghz or close to that. Industrial microwave devices tend to work at 915 Mhz. Also, if the frequency had something to do with it, then 2.4 Ghz would be the wrong one. The resonant frequency for water is somewhere in the 20 gigahertz range. The only reason 2.4 Ghz is used for microwaves is that it's a free bands of frequency (ISM frequency bands) that can be used worldwide.

As long as we're getting in the scientifically correct... Frequency does matter. If the frequency is too high, the dipole won't be able to follow and you'll see other phenomena pop up. That is, for instance, why water is blue. The frequency of the electrons around the dipole allow them to absorb a bit of red light. If you go even higher, it will stop interacting altogether. If you go too low, the energy transfer will be hindered.

Thanks. Much more informative. I always had a sense that the explanation about the frequency and water was suspect, but have read it several times, so went with it. So much for the Fox News approach to research...

Couldn't we attach batteries to hamsters and let them carry the electricity where it's needed? Just set up hamster base stations with battery chargers and hamster food, and place small pellets of hamster food in the battery compartments of the device needing power. It's so simple and easy, I'm surprised no one has thought of this before.

Does anyone know how much power is "wasted" (if any) due to using wireless methods versus wired connections?

Off my limited knowledge, it would seem to be akin to one of the problems with biofuels...they currently take more energy to produce than they store. So will using this technology to charge a device result in taking two or three times more energy to transmit the same amount of power to the device, or is there no discernible difference between wireless and wired?

All fuels take more energy to produce... in a sense, our present fossil fuel predicament is because we are using stored energy from the sun over millions of years. That we can even think about creating biofuels or really, any sort of fuel, efficiently, says a lot for how far the technology has come. But we'll never be able to just "create" a fuel, and the world's going to have to accept that.

Nuclear does "create" energy (unless, I suppose, you think of mass as energy). Granted, that energy is still not coming from nowhere, but when you get c^2 (the speed of light, squared) working in your favor, you're doing pretty darn well for yourself. I realize nuclear is still very hampered by practical issues, and I'm not particularly taking a stand for nuclear power over more dissipated forms (solar, biofuels)... but when you step back and think about releas

Nuclear does "create" energy (unless, I suppose, you think of mass as energy).

This is true of fusion, but fission is solar energy in the same sense that fossil fuels are. The energy was put in to the heavier-than-iron elements by fusion reactions in stars a few billion years ago.

Nuclear does "create" energy (unless, I suppose, you think of mass as energy).You know, E=mc^2 is valid for chemical energy, too. So by that same token, gasoline "creates" energy. Of course it's a much smaller fraction of the mass of the fuel.

200 years ago people would never fly.
150 years ago it was impossible to talk to someone in another town
125 years ago it was impossible to own a car
50 years ago it was impossible to own a computer (except for banks, schools, and gov't)

You never know what the future might hold. Cold Fusion might prove to be possible. Zero point energy might be proved and harnessed. Maybe someone will figure out a way to take the heat out of the atmosphere and make electricity from that.

My point is, and I do have one, that nothing is impossible. There is more that we don't know then we know... Chew on that.

Screw that! Lets just build ten mile wide/long automated tankards that go into space and collect chemical energy from the sun/solar winds/asteriods/???, and then bring it back to earth. When we get this working really well, the only waste will be heat - which we can actively concentrate and pump into space (with no net loss of mass for the process since we took on a lot from the tankards).

We can probably do a few dozen terajoules that way, and keep it up until t

Here's the Wiki [wikipedia.org] I found on general wireless energy transmission.

From the wiki article

"WiPower [1] technology is a very recent example of inductive charging technology. The charging pad allow users to charge multiple electronic devices that are placed on its surface. It is insensitive to the position or orientation of the devices under charge. Unlike most inductive charging systems, the WiPower system uses air-core technology which allows the system to be integrated into very small electronic devices. The efficiency of the system actually exceeds many corded chargers which have a median efficiency of 57%."

You had better believe there's a difference between transmitting energy wirelessly vs on a wire. The reason is that a wire simply transmits the energy end to end; the energy is essentially limited to the physical space of the wire. So some minor losses happen due to resistance, etc. But to transmit the power wirelessly means you have to radiate it in all directions. The amount of energy required to do wireless power transfer over a certain distance is basically governed (upper bound) by the inverse-squa

that's not entirely true as the target device could be targetted with a "power beam". i do agree however that it is still likely to be terribly wasteful. better local storage of energy is definitely a better idea.

i'm amazed at the battery life of the ipod classic, for example, as compared to that of the 4th generation ipod (in just 3 years went from 16 real hours to real life 30+ hours and it's smaller to boot)

I suspect the standby losses will be more than the 500-750mW allowed by efficiency standards [energy.gov]. These standards were set to challenge the manufacturers of conventional wire-connected power supplies. To meet them, the engineers must reduce losses wherever possible. Copper conductors can deliver power to the load device with efficiency better than 95% (less than 0.25V drop for a 5V adapter, etc.). Wireless couplers would be hard pressed to come anywhere close to that. It seems like a step backwards in the battl

At current, it takes more units of fossil fuel (from power plants) to produce biofuels than it would to simply have made and used gasoline. That's the point I was making that if your goal is to produce a fuel, you really shouldn't be using more coal/oil to make it than it would have taken to make and use gas to do the same thing. Obviously, a lot of that is a technology issue (compare the research done to date on refining oil to that of refining biofuels and see if there's not a century or two of disparity)

Shooting photons across a room to deliver significant power just ain't gonna be practical. If you use an omnidirectional antenna, the losses will be huge. If you instead have like a parabolic dish that tracks the receiver, the losses will be lower, but what happens to kitty or your eyeballs if they get in the way? Cooking your eyeballs to a nice firm egg-white consistency is not going to fly.

Magnetic fields are dipole fields, that means the little wavy lines leaving the North pole want to curl back as quicly as possible to the South pole. Which means they have very little extent in space. The strength drops off as the CUBE of the distance, so any significant distance is a no-go.

Maybe this is a good thing. I don't want my neighbour leeching my wireless internet AND my wireless power! Besides, I think a practical application of this would be as a laptop dock with no electrical connection. Place your laptop on the charging pad, and your laptop will start charging without having to plug in!

Besides, I think a practical application of this would be as a laptop dock with no electrical connection. Place your laptop on the charging pad, and your laptop will start charging without having to plug in!

At least if there's one thing we can be sure of judging from the last century or so of appliances is that each and every gizmo will have its own charging pad which will be absolutely incompatible with any other gadget you own. Those charging pads will also have "wall wart" transformers that only work with the pad they came with.

it may not make a replacement for everything, but unless I am mistaken I have already seen electric toothbrushes that use something similar over very short distances. the advantage is they don't have to insulate any leads or connectors from the water it will inevitably be exposed to. a sealed case is always better than a sealed case with a rubber plug over the one opening where you give it power. range is not an issue because you are still dropping it into a charging dock [sitting it right on the transmitte

That's not wireless (RF) like he's talking about, that's inductive. It works on the same principal as a transformer. It only works under VERY short distances. If you lift your toothbrush out of it's charger by a 1/2", it probably won't work anymore.

An RF system would let you use the toothbrush without having it charged in a station. You could hang it from the ceiling with a piece of twine, turn it on, and let it run until something physically wears out.

I agree with the GPP, it's impractical. Inductive coupling (which I think is the same as magnetic being discussed) makes far more sense.

I swear I saw a proof of concept from a Korean company that was a desk where the surface was made out of some mat material they made. You plugged the desk/mat into the wall then it powered everything you dropped on it. They had a clock, a radio, and a couple of other little things. I would love for all of my peripherals to be charged/powered just by being in contact with my desk. That would be excellent.

For the reasons you state, I'd put the people demanding wireless power among the people demanding pony-sized unicorns, at least for the forseeable future. I think pony-sized unicorns is more likely given how genetic engineering is going, but then the people that say they want them are going to say they won't pay more than $1500 for those.

you dont need to shoot it across the room, just charge the device when set on a table. Make ALL your tables charging stations and now you attain the "wireless power" illusion.

I did this way back in the 90's for one of my EE projects. I created a charge mat and charge adapters to make devices charge from the mat. worked great, erased tapes , credit cards, and discs though... All you did was set the device down and it started charging. worked great and could supply 100ma of charge current to 3 devices.

An average laptop consumes about 50 watts. Using the back of a 15" screen as receiver (0.07 m^2), the intensity is about 50 / 0.07 = 714 watt/m^2. As a reference, "a site in Eastern Oregon receives 600 watts per square meter of solar radiation in July". http://zebu.uoregon.edu/disted/ph162/l4.html >
See, it's just like walking by an unshaded window in a summer's day.

Yeah, those methods seem inevitably lossy to me. But what about lasers? How efficient are they? It seems like a microwave laser would transport energy efficiently... but I don't know how efficient the creation of the maser is in the first place.

All you do, you see, is you put this big coil above your car, and several gigawatts RF transmitters embedded in the roadway! Waste heat from the transmitters (and the melted tires, and the roasting humans) can even be used to ensure that ice never accumulates on the road!

Wireless power certainly should have a future if a single standard was achieved. It would be nice to be able to sit my child's toys near the charging station and have them charge themselves. No more fuss with changing batteries every month. No risk of losing the AC adapter.

And it can certainly be made efficient and safe by using a focus beam to the device being charged. We are surrounded by RF signals everywhere we go. What is one more RF signal?

How do you prevent arcing with wireless power? Seems to me that wireless power pretty much means arcing through the air of some kind for any high-power applications... sounds dangerous in the proximity of the broadcast and receiving antennae.

I'm not in the field. I'm not officially qualified to decide. But this is/.

Wireless (RF) worries me. You either have to confine it to a little beam (then why not just set the device down somewhere?) or pump a ton of power into it (most wasted). There are a few limited applications where it might make sense (the Wii, since we already know you'll be standing in front of the TV). I'm also worried about health concerns (really high frequencies can solve this, to a good degree) and interference (this is what I

Sometimes I can't help but think that if Tesla had continued more of his experimental research into very high energy RF transmissions that he might have learned about its hazards similarly, and personally, much in the same manner that Marie Curie learned the hard way about the hazards of working with radioactive substances without thorough understanding and laboratory safety.

Can someone explain if this is a matter of transferring electrons between two devices, eg the source and recipient of the energy? Wouldn't we be better off either A: improving batteries, or B playing with an source that creates an event that would cause a pendulum of sorts to charge a device?

Yes I am aware of that phenomena, it powers my flashlight:) What I am asking though is if there could be an event in a location such as a magnetic field that pulsed or something that could be used to control the rhythm of the wires so that when you were in a location where this event occurred the device's "Charger" would be able to use it to create a current without actually passing anything harmful through the air.

I dont think I am being clear enough with the magnetic concept or my understanding is too limited for this subject. Ok the best mechanical device I can think of off the top of my head is this:

Device A consists of an electromagnetic apparatus that 'pulses' on and off at a rapid pace. Device B has a coil and magnet with a spring. Every time device A pulses it causes Device B to cycle generating X charge. Obviously the efficiency rating would be low if only one device we

There is s vast difference between a universal wireless charging "surface" or "plate" where your electronics go at night versus recharging at a distance of 10 feet.

Then there is also a difference between the "idle" power loss versus "zero" while turned OFF & of the transmitters efficiency in getting power to a remoted device. I could imagine only 25% or less of the transmitter's input getting to the remote device.

Time matters. Batteries are going to get better quicker if A123Systems & others are right, meaning charging with a standard cord may be the cheapest & best method giving a 5-10 minute recharge, as opposed to overnight.

Ain't going to be easy. Lots of VC money is going to be burned up. The good news is the U.S. government is not picking and funding a single winner, as they tend to do when they back a "bill".

Even better than that, Tesla was able to power stuff at great distances. He was doing stuff like this as early as 1891. Really people ought to start giving Tesla his due and stop claiming his concepts for themselves. More on his wireless power experiments here [wikipedia.org].

Telsa was an absolute prodigy. It's a damn shame he is not more often mentioned in the history and school books!Don't know who he is? Take 10 mins. and see that he is an equal to names like Einstein and Newton:http://www.youtube.com/watch?v=gt8Y93k0pB0 [youtube.com]

Really, just do this, open your eyes!

He had wireless power working with his 'radiant energy' approach... almost with zero loss.

There is not a single student being taught the complete thing when it comes to EE. Maxwell's original theories have been simplified b

Tesla was a brilliant nut. Wireless transmission of power was EXTREMLY inefficient. In other words just like his Tesla turbine it has limited applications and really isn't better than what our scientists can do now. No magic, no strange conspiracies just reality. Not as much fun but it is the truth.

So where does the power go, that doesn't make it into the device? In this day and age of energy efficiency and conservation, this seems a step backwards. Maybe that energy is slowly heating the room or maybe it's slowly increasing my risk for cancer, but either way if the vast majority of the power isn't going into the device it's being wasted. Tis tech might have some specific applications where the wirelessness is of true overall benefit, but everyday hand held devices aren't it. As global energy demands continue to grow using something like this to charge your cellphone will become a hallmark of bourgeois ass-hattery.

I'm relatively pessimistic about both of the technologies mentioned due to the inherent limitations that they pose (large leakage of radiated power or short range). I'm looking forward to seeing products based on the wireless power idea that came out of the Joannopoulos group at MIT in 2006.The idea was that you can setup an RF wireless power transmitter in such a way that it does not actually transmit any power unless it resonantly couples to a precisely shaped receiver. This way there is little to no leakage and they claimed that the power transfer was quite efficient. I'm sure this was posted to slashdot, but I can't seem to find it. Here's a link to the paper if you are somewhere with access to Science: Science 6 July 2007: Vol. 317. no. 5834, pp. 83 - 86 [sciencemag.org] and here's [mit.edu] a link to the press release by the MIT news office (no subscriptions required).

Sorry but you have this one wrong - converting mains AC to 1mhz is very easy. A common switch mode power supply chops the 50/60hz AC from the wall into a 100khz to 1Mhz waveform with a common (but fast) MOSFET. The chopped signal is then run through a stepdown transformer. The transformer and ripple filtering capacitors in the second stage can be MUCH smaller and more efficient due to the higher input frequency. In this way the high frequency generation is effectively free for a wireless power system, since most DC converter will have a high frequency first stage anyway.

Thanks for the info, I did a quick search to see if it was being commercialized and found nothing. That link showed something that makes me pause though, the receiving coil looks HUGE! I am assuming that to get to a smaller coil they would have to use a higher frequency field which I'm assuming will decrease range. Hmmm. I guess I should just do the math myself and see....

Yea, this group is doing what tesla did a hundred years ago, but it's still neat. They currently are on what would be considered "the cutting edge" of this field, no pun intended. The thing that's been a killer in the past has been the power generation and conversion efficiency (30%). The trick is getting power electronics to switch at ~10MHz without losing 60% of your total power input. The thing that makes all of this so interesting, is that advances in SiC (silicon carbide) technology are just opening up

The focus shouldn't be on "wireless" power per say, but in general just absorbtion of energy which doesn't require a tether, AKA solar & etc. to an extent. RF may be possible but I'd be damn weary if there weren't some massive long term safety tests first.

The problem with wireless power transmission is that it's hard to control where your electromagnetic fields go. They tend diverge as an inverse square law, scatter and bounce all over and be absorbed by things that are not your antenna. This is wasteful, because your wireless power ends up heating up trees, grass, and rivers rather than powering your city, and dangerous, because if a human absorbs even a tiny fraction of a gigawatt power transmission from a generation plant, he'll be cooked.In recent year

Well first of all, the biggest untapped energy source on the planet still is an increase in efficiency. Why does my laptop need take 60 Watts of power in order to heat up my lap?Why do we have displays in mobile devices that waste 5/6 of the light they generate?Why do we still have processors that take _Watts_ of power althought alternatives with milliwatts are available?I believe that a 1 Watt laptop-like device is definitely possible. It won't have a colour screen nor Windows Vista, but it would do everyt

The Asus Eee PC is at ~11W TDP in it's current version, and the next one is rumored to drop to ~7W TDP, which should be low enough to lose the fan, and thus have no moving parts at all. And this is a proper little laptop with a color display (LED backlit, of course) and enough oomph to run Linux, BSD, WinXP and even Vista if you're feeling masochistic:-)

As I pointed out previously [slashdot.org], there were at least three companies demonstrating wireless charging systems.
This new article lists two more, Powercast and Fulton Innovation.

Short-range systems using long-wave near-field RF are probably the way to go. Power ratings can be quite high. The GM EV-1 charger used an inductive paddle operating at 400KHz, and could transfer kilowatts across about half an inch at 90%+ efficiency. The MIT system [technologyreview.com] operates in the 4-10 MHz band.

One of the big advantages to this idea is not having to have a bazillian different wall warts for every separate device. Usually unlabeled so that 6 months later, you have no idea what goes with what if you haven't rigorously kept things together and/or labeled them yourself, not to mention having to lug around a few kilos of the things when you travel.Except now they're going to beta/vhs us so some things need this charger and some need the other charger. If you get it wrong 6 months later, you've got a

In a sense, we've standardized our "wired power connectors" with the 120V (US) outlets. The devices haven't standardized their power inlets though, so we have a bazillion adapters.That would be the advantage of the rf method though: even if there were multiple incompatible formats, at least the device could pick up whatever it needed. You'd still have to carry the transmitters around unless they became ubiquitous though. That would be nice, but seems like the long shot, both for health concerns (valid or

I don't even understand why there's a question. Magnetic coupling is a joke, sure it's efficient, but really, is it ALL that different from a form-fitting cradle with physical contacts? You still have to put the device within inches of the charger... are people REALLY that lazy that they won't go the extra inch? I have an electric toothbrush that just sits in a cradle every night, I don't even SEE any physical contacts, and it's a good holder, so why bother? Or how about Apple's magnetic plugs, that's anoth

The thing I'd really like to see wireless power for? Transportation, by building this system right into the roads and billing your car for the amount of electricity used. Cars would be lighter, reducing the amount of electricity that would be required to move the vehicle. This would also eliminate the need for batteries meaning unlimited range. I'd be interested to see what would happen to automotive design if the power plant of a car was no longer necessary.The only problem with this is the engine/batt

For the types of application this is meant for, I think the old option would be a power cable. Unless you want to run your TV and computers from a few truck sized batteries. Seriously, when they brought out laptops did you say "JUST USE A DESKTOP!"? When they invented the telephone would you have said "JUST GO FOR A VISIT!". When people are walking into hospital do you should "JUST DIE ALREADY!"?